Common Side Effects of Probiotics



If you have IBS or other digestive issues, taking a probiotic supplement or eating fermented, probiotic rich foods seems like the logical next step. You may have been recommended this by a doctor or nutritionist. However, probiotics can sometimes make things worse when used straight away for a lot of people with significant gut dysfunction or dysbiosis, and don’t always work. This post will shed some light on why probiotics sometimes make your symptoms worse and what to do about it.

Here’s what we’re going to cover:

  • The benefits of probiotics.

  • The most common side effects of probiotics.

  • Why probiotics can make your symptoms worse.

  • How to pick a probiotic supplement.

  • How to titrate your dose to minimise IBS symptoms from probiotics.

What are probiotics

According to the WHO’s definition, Probiotics are live microorganisms, typically bacteria or yeast, that give us health benefits when ingested in sufficient amounts. The most common species that we see in our supplement probiotics are strains of bifidobacterium and lactobacillus. Probiotics have many potential health benefits including:

  • supporting immune system

  • improving digestive function

  • increasing absorption of nutrients

  • preventing and treating UTIs

  • reducing symptoms of IBS and IBD

It’s important to note that most probiotics don’t colonise the gut i.e. set up shop and live there. They pass through the GI tract and play useful roles along the way, and help existing colonies of beneficial bacteria to grow and proliferate.

Most common side effects of probiotics

Despite their proven health benefits (for those who tolerate them really well), for those who don’t tolerate them, the most common side effects of probiotics are:

  • Gas

  • Bloating

  • Looser stools

  • Abdominal pain

For most people, these side effects are short lived and just take a week or so of adjusting to introducing new bacteria.